The purpose of the project is to elucidate the interaction of polymers used for specific implants with the physiological environment and to explore specially prepared polymers and design features with respect to their suitability and performance in a variety of contexts. Implants will be examined after removal for lipid absorption, protein deposition, changes in surface-free energy, and alteration of physical properties. Prostheses such as artificial hearts, heart valves, vertebrae, and catheters will be employed. Observations should include SEM, infrared spectroscopy, contact angle measurements, tensile property measurements, and energy dispersive x-ray analysis.